So called capless refueling systems are known. Such systems typically use a two-part cover assembly to seal the fuel pipe when a supply nozzle is not in place. A first part of the assembly which is referred to as the primary shut off valve or PSV typically includes a valve element such as a float valve or the like which is normally held closed by a spring which is mounted at a bracket at the interior of the PSV. The PSV which houses the spring, the spring mounting bracket and the valve element is snapped into the interior of the contoured fuel pipe. In a known prior construction an upper cover which houses an upper flapper valve snaps around the outer diameter of the fuel pipe over the top of the PSV. Both the PSV and the upper cover are retained by engaging slot openings disposed around the perimeter of the fuel pipe. That is, portions of the PSV and the upper cover snap into slot openings in the fuel pipe.
As will be appreciated, it is undesirable to permit moisture to enter the fuel supply. However the slot openings in the prior construction may act as an entryway for the introduction of moisture from the environment. To prevent any introduced moisture from entering the fuel supply, an O-ring or other body seal element is typically positioned in the annular region between the fuel pipe and the PSV body at a position axially below the slot openings in the fuel pipe. In this construction it is desirable to avoid having radial openings in the PSV body at positions above the body seal since such radial openings would provide a potential bypass flow path around the body seal. Accordingly the spring which biases the valve element in the PSV is typically mounted on a dedicated bracket that is fully contained at the interior of the PSV body. While such prior systems are highly functional, the need to mount a separate spring bracket at the interior of the PSV body results in added complexity.